This invention relates to a cylindrical lock for mounting on a door panel and, in particular, to an improved cylindrical lock assembly for use with lever-type handles.
Cylindrical locks utilized in exterior door applications must be made to withstand more severe environments and higher security usage than those utilized on interior doors. This is especially true where the cylindrical lock is utilized in conjunction with a lever type handle. Such high security exterior cylindrical lock assemblies are subject to damage by vandalism, burglary, and abuse. Damage is often magnified by the availability of the lever handle to exert considerable torque on the cylindrical lock assembly. When such cylindrical lock assemblies are overloaded, they may jam and disable the assembly, or they may even damage it to the extent that the door may be forced open. Even if such lock assembly is still functional after abuse, the lever handles themselves may be damaged and require replacement or repair.
While the prior art discloses various types of cylindrical lock assemblies, few if any are appropriate for the heavy duty security type usage required in many applications. U.S. Pat. Nos. 3,985,008 and 4,604,879 disclose different types of configurations which strengthen the attachment of the cylindrical lock to the door panel. However, neither of these configurations for securing lock chassis are considered suitable for the most severe environments.
Bearing in mind the problems with prior art cylindrical lock assemblies, it is therefore an object of the present invention to provide an improved cylindrical lever handle lock which is highly resistant to abuse, vandalism and damage in general.
It is another object of the present invention to provide a strengthened cylindrical lock assembly which is easily installed in conventional door openings.
It is a further object of the present invention to provide an improved cylindrical lock assembly which resists damage and wear to the positioning of the lever handles.
It is yet another object of the present invention to provide a strengthened cylindrical lock assembly which may be easily manufactured.